The 3126B and 3126E engines are in-line six cylinder
arrangements. The firing order of the engine is
1-5-3-6-2-4. The engine’s rotation is counterclockwise
when the engine is viewed from the flywheel end of
the engine. The engine utilizes a turbocharger and
an air-to-air aftercooler. The engines have a bore of
110 mm (4.3 inch) and a stroke of 127 mm (5.0 inch).
The displacement is 7.25 L (442 cu in).
The hydraulic electronic unit injector system (HEUI)
eliminates many of the mechanical components
that are used in a pump-and-line system. The HEUI
also provides increased control of the timing and
increased control of the fuel air mixture. The timing
advance is achieved by precise control of the unit
injector timing. Engine rpm is controlled by adjusting
the injection duration. A special pulse wheel provides
information to the Engine Control Module (ECM) for
detection of cylinder position and engine rpm.
The engine has built-in diagnostics in order to ensure
that all of the components are operating properly. In
the event of a system component failure, the operator
will be alerted to the condition via the check engine
light that is located on the dashboard. An electronic
service tool can be used to read the numerical code
of the faulty component or condition. Also, the cruise
control switches can be used to flash the code on the
check engine light. Intermittent faults are logged and
stored in memory.